Thermal energy (i.e., heat energy) is a byproduct of normal operation of electrical circuitry. Thermal energy is generated as a result of frictional effects of charge flow during operation of the electrical circuitry. If the thermal energy is not dissipated, a buildup of such energy in the electrical circuitry (and circuit elements thereof) can result in inefficient or abnormal operation of the circuitry. Furthermore, the buildup of thermal energy can result in damage to the circuit elements of the electrical circuit.
Computer circuitry is an example of electrical circuitry which generates thermal energy as a byproduct of normal operation thereof. Computer circuitry oftentimes comprises a plurality of circuit boards which have edge connectors to permit plugged connection of the circuit boards to a computer backplane, commonly referred to as a computer motherboard. The circuit boards and the computer motherboard are typically housed within a supportive enclosure, such as a cabinet.
By merely plugging the circuit boards of the computer circuitry into the computer motherboard to be in the plugged connection therewith, electrical circuits disposed upon the circuit boards become connected to the motherboard and to each other by way of the motherboard. Reconfiguration of the computer circuitry is effectuated merely by addition or substitution of circuit boards having different circuits disposed thereupon.
The circuit boards of the computer circuitry are oftentimes positioned in a fairly dense arrangement within the supportive enclosure, and thermal energy generated during operation of the circuitry is not easily dissipated. If the thermal energy generated during operation of the computer circuitry is not properly dissipated, the aforementioned problems associated with buildup of thermal energy during operation of electrical circuitry can occur.
Heat dissipative apparatus is utilized to dissipate the thermal energy generated during operation of the computer circuitry (as well as other electrical circuitry) to prevent the buildup of thermal energy.
Convection-type, heat dissipative apparatus is a relatively inexpensive means by which to dissipate thermal energy generated during operation of the computer circuitry.
A heat sink comprised of a thermally-conductive material is an example of heat dissipative apparatus which dissipates thermal energy by convection. A heat sink is positioned in close physical proximity to circuit elements of the circuitry, and a thermally-conductive path is created between the circuit elements and the heat sink to permit thermal energy contained in the circuit elements to be conducted to the heat sink whereat the thermal energy is dissipated by convection. A fan is another example of heat dissipative apparatus which dissipates thermal energy by convection. A fan is operative to generate an air flow which assists in the dissipation of thermal energy. A fan is oftentimes used in conjunction with a heat sink.
Convection-type cooling apparatus is, however, inherently inefficient and is sometimes inadequate to dissipate adequately the thermal energy generated during operation of the circuitry, particularly when significant amounts of thermal energy are generated during operation of the circuitry.
Dissipation of the thermal energy generated during operation of the circuitry may also be facilitated by controlling the ambient temperature of the environment in which the circuitry is positioned. Computer circuitry, for instance, is sometimes positioned within a refrigeration unit. The lowered temperature of the air within the refrigeration unit permits dissipation of greater amounts of thermal energy generated during operation of the circuitry.
To permit access to the circuitry positioned within the refrigeration unit, the refrigeration unit oftentimes includes an access door. However, when the access door is opened to access the circuitry positioned within the refrigeration unit, warmer air from outside of the refrigeration unit mixes with cooler air within the refrigeration unit.
Problems can occur as a result of this mixing as, at lower temperature levels, the moisture-containing ability of the air is lower than at higher temperature levels. Moisture (i.e., water vapor) contained in the air at warmer levels condenses as the temperature levels of the air are reduced.
Once the access door of the refrigeration unit is reclosed and the refrigeration unit cools the warmer air mixed with the cooler air, water vapor condenses into liquid form.
Condensation of the water vapor into the liquid form can deleteriously affect operation of the circuitry positioned within the refrigeration unit if the vapor condenses upon the circuitry. As water is electrically-conductive, water vapor condensed upon circuitry can cause short circuiting of the circuitry. Hence, placement of computer circuitry within refrigeration units is oftentimes an unacceptable manner by which to assist in the dissipation of thermal energy generated during operation of the computer circuitry.
When the computer circuitry is comprised of superconducting devices, thermal energy generated during operation of the circuitry may be dissipated by placement of the circuitry within an inert liquid, such as liquid nitrogen. However, use of the inert liquid is not practical in normal applications.
Heat exchanger systems are also sometimes utilized to dissipate thermal energy generated during operation of computer circuitry. In a heat exchange system, a coolant fluid is circulated proximate to the circuitry, and thermal energy generated during operation of the circuitry is transferred to the coolant fluid as the coolant fluid circulates. However, once installed, existing heat exchanger systems for computers either cannot be altered to supply coolant fluid to additional, or alternate, locations, or can only be altered to supply the coolant fluid with significant difficulty.
It is with respect to these considerations and other background information relative to existing heat dissipative apparatus that the significant improvements of the present invention have evolved.